High thermopower and power factors in EuFeO3 for high temperature thermoelectric applications: A first-principles approach

Abstract

Thermoelectric materials that can work at operating temperatures of T ≥ 900 K are highly desirable since the key thermoelectric factors of most thermoelectric materials degrade at high temperatures. In this work, we investigate the high temperature thermoelectric performance of EuFeO3 using a combination of first-principles methods and semi-classical Boltzmann transport theory. High temperature thermoelectric performance is achieved owing to the presence of corrugated flatbands in the valence band region and extremely flatbands in the conduction band region. The lowest energetic structure of EuFeO3 lies within a G-type antiferromagnetic configuration, and the effect of compressive and tensile strains (−7% to +7%) along the (a, b) axes on thermoelectric performance is systematically analyzed. An extremely high value of the Seebeck coefficient (more than 1000 μV/K) is consistently recorded in the high temperature region between 900 K and 1400 K in this material. Furthermore, electrical conductivities and power factors are high and electronic thermal conductivities are low in the considered range of temperatures. The calculated theoretical minimum lattice conductivity is small, estimated at around 1.47–1.54 W m−1 K−1. A compressive strain of −3% is revealed to be the optimum level of strain for enhancing the key thermoelectric factors. Overall, p-type doping shows better thermoelectric performance than n-type doping in EuFeO3.

Methodology to Probe Disorder Contribution in Raman Linewidth via Optical Absorption Spectroscopy in Orthoferrite EuFeO3

“…67 Furthermore, Sarikhani et al 68 had explored the photocatalytic properties of EFO nanoparticles under visible light, which revealed remarkably efficient photocatalytic activity along with reusability and stability for the nanocomposite of EFO with TiO 2 contributed by reduced electron−hole recombination. In another report by Iyyappa Rajan et al, 69 thermoelectric (TE) properties of the EFO compound have been studied via the first-principle approach that suggested high stability and large values of TE parameters for this system at elevated temperatures, where even the key TE factors of most TEmaterials degrade. Since these properties are essentially a function of the lattice dynamics, they may be affected by the presence of disorder, which has been the motivation for the choice of this correlated system�EuFeO 3 in the present study.…”

Influence of a compressive strain on the high-temperature thermoelectric properties of europium orthoferrite

“…Our work shows for the first time that such features in the band structures are also present in EuFeO 3 that makes it viable for high-temperature TE operation [5]. Furthermore, TE transport properties of EuFeO 3 were probed by introducing strain into the system.…”

“…The general methodology regarding the electronic band structure and density of states calculations using the first-principles density functional theory method was already outlined in our previous paper [5]. For this work, we focus on the transport properties calculations using the AMSET code.…”

“…Adding to the pool of high-temperature TE studies, we have recently published our work that investigates the TE potential of europium orthoferrite (EuFeO 3 ) for high-temperature applications [5]. Here, we have seen that the presence of corrugated flat and flat bands in EuFeO 3 and the presence of large band gap contribute to its high thermopower and large PFs for 900 K-1400 K. This relationship between the Seebeck coefficient to the corrugated flat bands and flat band structures were similarly observed in the case of PtSb 2 in [6], of nitrogenated holey graphene in [7], and of Si-doped InSe in [8].…”

“…Our recent study on EuFeO 3 has presented an important development in high-temperature thermoelectricity, as it yielded significantly high values of Seebeck coefficients for temperatures between 900 K and 1400 K [5]. Transport calculations were performed using BoltzTraP2 [9,10], a program widely used to calculate various TE transport properties such as the Seebeck coefficient, electric conductivity, electronic thermal conductivity and PF.…”